PEX ID vs Pipe ID

Question about the ID of PEX say 1/2" 0.475 inches and galvanized pipe 1/2" ID of 0.622. When a 1/2" supply line is requested which to use? There is a difference in the ID's and that will noticeably effect water volume. Thanks

Under no circumstance should you be using galvanized pipe

OK, understood Matt30. My question then is will 1/2" PEX deliver enough water volume for my washer? shower? sinks probably? dishwasher too? or should I use 3/4 PEX all the way? Thanks

Run a 3/4" main with 1/2" branches to each fixture.

How many fixtures do you have to serve? And how many storeys are you going from your pressure tank to furthest away fixture?

The general guideline for your average house is run all your main lines in 3/4", and branch off in 1/2" for your fixtures.

Personally myself, i like to bring 3/4" to within a foot of the shower fixture or somewheres close. Doubtful that it actually makes a difference, its just how i started doing it to guarantee the volume was there, and i stuck with it.

If you run your waterlines by that guideline, you wont have any issues using pex as long as it isnt some monster of a house or something.

If you want a little more peace of mind about your volume, use the Wirsbo "Quick & Easy" fittings with the expansion rings. The fittings themselves are the same ID as the pipe, allowing a little more flow compared to traditional crimp.

Damn it. johnjh20 swoops in and steals the show as im typing. I gotta get faster.